Guangyu Han | Searcharxiv

arXiv2021

Reinforcing increase of {\Delta}TC in MgB2 smart meta-superconductors by adjusting the concentration of inhomogeneous phases

Incorporating with inhomogeneous phases with high electroluminescence (EL) intensity to prepare smart meta-superconductors (SMSCs) is an effective method of increasing the superconducting transition temperature (Tc) and has been confirmed in both MgB2 and Bi(Pb)SrCaCuO systems. However, the increase of {\Delta}Tc has been quite small because of the low optimal concentrations of inhomogeneous phases. In this work, three kinds of MgB2 raw materials, namely, aMgB2, bMgB2, and cMgB2, were prepared with particle sizes decreasing in order. Inhomogeneous phases, Y2O3:Eu3+ and Y2O3:Eu3+/Ag, were also prepared and doped into MgB2 to study the influence of doping concentration on the {\Delta}Tc of MgB2 with different particle sizes. Results show that reducing the MgB2 particle size increases the optimal doping concentration of inhomogeneous phases, thereby increasing {\Delta}Tc. The optimal doping concentrations for aMgB2, bMgB2, and cMgB2 are 0.5%, 0.8%, and 1.2%, respectively. The corresponding {\Delta}Tc values are 0.4, 0.9, and 1.2 K, respectively. This work open a new approach to reinforcing increase of {\Delta}Tc in MgB2 SMSCs.

cond-mat.supr-con↗

arXiv2019

Smart metastructure method for increasing TC of Bi(Pb)SrCaCuO high-temperature superconductors

Improving the critical transition temperature (TC) of Bi(Pb)SrCaCuO (B(P)SCCO) high-temperature superconductors is important, however, considerable challenges exist. In this study, on the basis of the metamaterial structure and the idea that the injecting energy will promote the formation of Cooper pairs, a smart meta-superconductor B(P)SCCO consisting of B(P)SCCO microparticles and Y2O3:Eu3++Ag or Y2O3:Eu3+ luminophor was designed. In the applied electric field, the Y2O3:Eu3++Ag or Y2O3:Eu3+ luminophor generates an electroluminescence (EL), thereby promoting the TC via EL energy injection. A series of Y2O3:Eu3++Ag topological luminophor-doped B(P)SCCO samples was prepared. Results showed that Y2O3:Eu3++Ag was dispersed around B(P)SCCO particles, forming a metastructure. Accordingly, the onset transition temperature (T_(C,on)) and zero resistance transition temperature (T_(C,0)) of B(P)SCCO increased. Meanwhile, the B(P)SCCO sample doped with 0.2 wt% Y2O3 or Y2O3:Sm3+ nonluminous inhomogeneous phase was also prepared to further prove the influence of EL on the T_C rather than the rare earth effect. Results indicated that the TC of the Y2O3 or Y2O3:Sm3+ doping sample decreased. However, the TC of the 0.2 wt% Y2O3:Eu3++Ag or Y2O3:Eu3+ luminophor-doped sample improved. This outcome further demonstrated that the smart metastructure method can improve the TC of B(P)SCCO.

cond-mat.supr-con↗